The present invention relates to an elastic floor covering in the form of sheets, which can be rolled up and have a soft core of polyurethane and a layered compound structure disposed on the core.
Such floor coverings have been produced for a long time already from plastic materials, such as PVC or linoleum. Furthermore, polyurethane is suitable as a material for such floor coverings. For example, a floor covering is known from the international patent application WO2013/064160 of the applicant, for which at least the core consists of polyurethane, which is obtained from a polyester polyol of renewable raw materials and aromatic isocyanate. Among other things, this involves advantages with respect to environmental compatibility. This floor covering, furthermore comprises a decorative layer, which is disposed on the core, and a wear-resistant use surface. Within the scope of the present application, the layers on the core generally are to be referred to as a layered compound structure, it being noted that this layered compound structure may also be arranged differently, and, for example, may have additional or different layers. The concept of the layered compound structure, used here, accordingly, is not limited to the sequence of layers, which is described in WO2013/064160.
Because of its flexibility, such a floor covering can easily be delivered in roll containers and laid by gluing it to the screed. The flexibility also leads to positive use properties, such as a good footstep sound insulation. Depending on the use of the floor covering, the dimensional stability, the impression behavior under load and the athletic functionality with regard to force reduction may also often be of decisive importance for its quality.
In order to be able to glue the floor covering reliably over its whole surface to the substrate, the back of the covering must be able to form a good bond with the adhesive. Therefore, until now, it was customary to grind the back of the floor covering or to provide it with a surface structure, such as a honeycomb structure or the like, into which the adhesive can penetrate well. In spite of these additional measures, the bond between the dispersion adhesive and the back of the floor covering frequently is unsatisfactory. It is, moreover, desirable to improve the above-mentioned positive properties of the floor covering even further, also by an appropriate design of its back.